Before the War of the Ring, a traveller approaching Isengard from the south would have encountered its forbidding guarded Gate set into the heavy wall of its Ring, and beyond the Gate the mechanised wasteland of Saruman its master. During the War, the Ents of Fangorn defeated Saruman and took over control of Isengard. The changes they made were extraordinary, so that the same traveller coming to Isengard after the War would have found the walls and the Gate entirely gone. In the place of the Gate stood two tall trees, through which a green path led into a garden of woodland and orchard.

The path led on between the trees towards the old centre of the Circle of Isengard, the great Tower of Orthanc. That Tower had been made of stone unbreakable even by the Ents, so they left it in place but surrounded it with water. After their work was complete, Orthanc rose from a rocky island in the middle of a clear lake that reflected the image of the great four-horned Tower.

Treebeard named this new region of park and woodland the 'Treegarth of Orthanc', where 'garth' is an old name for an enclosed space or garden. Indeed he may have intentionally chosen to call his new forest a 'treegarth' as a play on the original name of the place, Isengard. The '-gard' element of that name is etymologically connected to 'garth', and in these terms the Ents had taken a place that had been named 'irongarth' and made it a 'treegarth' instead.

Notes

1

22 AugustIII 3019 is the date that the Travellers came to Isengard on their journey northward after the War of the Ring, and found that Treebeard had filled the Circle of Isengard with a garden of trees. Isengard was known to have been ruinous on 5 March of the same year, so the gardens of the Treegarth must have into existence within the approximately six months between that date and 22 August. We know that the Ents could move trees with astonishing speed, but establishing the complete garden, with its stream and central lake, presumably took some considerable time.